Explosively driven stud with knockoff head portion



Nov. 13, 1951 R. TEMPLE 2,575,079

EXPLOSIVELY DRIVEN STUD WITH KNOOK OFF HEAD PORTION Filed May 15, 1949 INVENTOR. .Poseer EMP/.5.

Patented Nov. 13, 1951 OFF HEAD PORTIGN i yRober-'t Temple, SWissvale, ple VelocityfEquipment,

Paafassignor to Tem- Inc., Wilmington,-.Del.,

acorporation of Delaware Application May' 13, 1949,- Serial No. 92,974

1 Claim. (CL-85-28) This invention rela-testo ystuds adaptedito -be driven into objects fromexplosive-actuated tools.

A well-designed explosive-actuated tool has a shoulder in the barrel near its loutlet or muzzle for stopping the pistonV that -drives a stud out of thebarrel when an-explosive charge behind -the piston is fired. The principal purpose of the piston is to reducerecoil of the 'tool as much-as pos` sible. -It does this by striking the shoulder and thus-tending to,` drive the tool ahead-only a mment after the expanding gases in the Vbarrel attempt to drivethe'rtool backward. These two forces, acting in opposite directions, substantially counteracteach other sothatthere is veryilittle recoil. Howeverfin'order to obtain'this result, it is'necessar-ythat the toolibedesignedwith the arresting Kshoulder theproper distance fromV the object against whichthe muzzle isheld. If `the shoulder is too close to that object, the stud will come to rest Withoutlthe piston strikingthe-shoul-- der. `This willcause considerable recoil.' On the other hand, if the shoulder is too far from the work, the piston will strike the shoulder with a greatdeal of Yforce because it-will not be stopped bythe stud coming to rest in ithework..A In suchY a case thelpiston is' likely to press `itself into'the opening-beyond the shoulder, as if it were starting to extrud'e through that opening.

It is not difficult-to position the erly for shoulder prop- .a stud of a given size and an penetration linto the objectlintowhich it is tobe driven. =Di-niculty arises, however,l ywhen the length of theheado'f the stud is fchan'ged, be cause v-that'will affect the position ofthe piston relative to the arresting shoulder at the moment the stud comes to rest. Thus, if the-lhead is made shorter than th'e'heador whichrthertool is Ade signed, it Ehasthesame eifecteash makingthe shoulder :too far from the end of the barrel. If the head is made longer than the standard stud head, it is thersame as locating the shoulder too closefto 'the end. of 1 the `barrel; #in -the-rst case, the piston may become jammedfinfthefopening beyond the shoulder, Awhile in. thefsecond case there will be too much recoil.

It is'among the objectsofrthis invention' to provide ,studs oft-he type Aunder discussion which have permanent 'heads of v*different lengths, but with which vthe-driving piston always travelsl substantially the`V same distance through the driving tool barrel.

In accordance with this invention, a stud has an elongated driving head integral with one end of a shank. The opposite end of the shank is pointed. The diameter of the head is reduced expectedl at a `predeterminedfpo'int Ato weaken it ithere so that the portion of the head between its free end and zits Aweakened point can beknocked 'oil after the fstudlhas been driven into an object by an explosive.;actuatedtool; Theportion of the head remaining "aterY the `temporary npart has been knockedofi "will form `theperrnanent head of the stud; Thus, aplurality of studs `having driving heads @of uniform=1engthoan vbe provided with permanentheads having predetermined lengths differing fromloneranother.

The preferred'fembodimentof .the inventionis illustrated. in the accompanying drawings, in whichllig. Vlfis a vertical section through a drivingritool `barrel-and the obects into which the stud, shown 'inHeleVatiOn-,isto be driven'g. 2 is aside view ofthe studaiter it has been driven; Fig is asimilar view of the stud after the upper end ofits driving 'head has been knocked off; and Fig. 4 is a view similar to Fig. 2, showing a stud withftemporaryfand permanent head portions of different lengths than those shown in Fig. 2.

lReferring to' Fig. 1 of the drawings, the barrel I o'f-thedriving tool may be of any suitable form, the one `shown being part'of the tool disclosed in my'oopending patent application, Serial Number 34,542,'led June-22, 1948, nowPatent 2,479,431, issued -fAugust '116,' 1948.H The barrel is mounted in a barrel .guide lor sleeve 2 and has a threaded rear end screwed into a breechblock 3. The breechblock is provided vwith an axial passage 4, through lwhich a firing pin 5 can be projected. The firent-.end ofthe barrel is formed by a muzzle block I6 providedwith an internal shoulder 'l having anV inner diameter that is slightly less than the mainaxial bore 8 through thel barrel. The rear end of the axial bore is enlarged slightly toreceive va loaded cartridge 9, the rim of which is clamped between thebreechblockand the rear endfo'f the barrel. -Theffront end of the cartridge case is-compressed around a forwardly vtapered rear port-ion ll of a one-piece pistonyas shown inlig. 1 Vand in my copending patent application, Serial Number 43,746, led August l1, 1948, now abandoned. Inother words, the front end'ofthe case is tapered and `engages the forwardly convergingsurf-ace of the piston. The front portion 12=-of thev piston is cylindrical and fits -slidably in the barrel 4directly in front of the enlarged rear end voibore 8. f The'cartridge contains the usual charge of powder that is detonated by the firing pin.

Attached to the front of the piston by a separable connection is a metal stud l5 which is to be driven out of the barrel and into the objects that are to be fastened together by the stud. The connection between the stud and piston preferably is a friction connection, such as is provided b y a snug fit between an axial projection I6 on the front end of the piston driven into an axial opening in the rear end of the stud. This connection not only holds the stud and piston together after the cartridge is red, but it supports the stud in the center of the barrel spaced from the wall of bore 8, because the maximum diameter of the stud is less than that of the piston so that the stud can pass through the muzzle block 6 whose shoulder 1 stops the piston.

driven.l The rear end'of the shank is enlarged to form a driving head I1 that generally is considerably longer than the head that it is desired the stud should have after it has been driven. The head preferably is circular in cross section, and it is the rear or free end of the head that is provided with theaxial opening in which the projection I6 on the piston is inserted. After the barrel has been loaded with the stud, a metal washer I8 is inserted in a socket I9 formed in the outer end of the muzzle block. When the barrel is held vertical, the washer can be retained in the socketAby a little grease rst applied to the washer. The washer preferably projects from the socket.

The stud can be used for fastening various objects together, or it can be driven into a single object and its head used for fastening something to it by providing the head with screw for the purpose of fastening a wooden Stringer like to a concrete foundation 22 or supe port. The washer I8 is employed to increase the effective diameter of the head of the stud, so as to prevent the head from sinking into the wood.V

the enlarged portion of the barrel bore. This results in the piston and stud having a high velocity from the moment that they leave the'cartridge. The length of driving head I1 is so related to the height of shoulder 1 above the wood that the stud will come to rest in the wood and concrete just as, or slightly before, the piston strikes the shoulder. At practically the same moment that the tool starts to recoil, the shoulder 1 in the recoiling or rising barrel will strike the piston and thus counteract the recoil. This impact also will release the piston from the head of the stud.

It is a feature of this invention that studs, all having driving heads of the correct length for proper operation of the tool, can be provided with permanent heads shorter than the driving heads and diifering in length from one another to any desired extent. Accordingly, as

shown in Figs. 1 and 2, the diameter of the driving head is reduced, such as by an annular groove 25, at a point spaced from the upper end of the shank such a distance as to provide between that point and the shank a permanent head 26 of the desired length or height. The head is weakened suciently to permit the portion 21 of the head between its free end and the weakened point to be knocked oi readily after the stud has been driven, thereby leaving only the permanent head as shown in Fig. 3. The weakening of the driving head preferably is accomplished by tapering it toward the shank.

As shown in Figs. '2 and 4, the height of the permanent head will depend upon the length of the knock-oir portion, which in turn depends upon the location of the groove 25 that weakens the driving head I1. This groove can be located at any point along the driving head. In every case, however, the length of the driving head is the saine so that during driving of the stud objectionable recoil will not occur no r will the piston attempt to squeeze past the arresting shoulder 1 in the muzzle block.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claim, the incically illustrated and described. claim:

The combination with a .driving tool having a barrel containing an explosive-actuated piston near its inner end and a piston-stopping shoul-y der near its outer end, of a stud having an elongated cylindrical driving head formed for temporary connection to said piston and integralwith one end of a shank that a pointed piercing end, the head diameter than the shank and being provided with a peripheral groove at a predetermined point to weaken it, and the diameters of the poris provided with having a greater REFERENCES CITED The following references are of record in the nie of this patent:

UNITED ySTATES PATENTS Number Name Date 120,577 Farrel Nov. 7, 1871 1,696,523 Cochran Dec. 25, 1928 2,050,047 Febrey Aug. 4, 1936 2,405,897

Milone et al. Aug. 13, 1946 the head is thev 

